Preparation of tannin gel by enzyme-mimetic reaction of condensed tannin without use of crosslinking agent

Preparation of tannin gels was attempted by means of enzyme-mimetic reaction of condensed tannin without use of crosslinking agent. The gelation of condensed tannin was performed in the presence of H₂O₂ catalyzed by hematin of a ferriprotoporphyrin complex in water. The compressive measurements of the gels obtained by the 30–50 wt% concentrations of the tannin using 0.20–0.50 ml of 30 w/v% H₂O₂ aq. were examined. There is a tendency for the compressive properties of the gels obtained from the higher concentrations of the tannin and the larger amounts of H₂O₂ to be superior. The obtained gel was characterized by means of IR spectroscopy. Moreover, the obtained tannin gel was compatibilized with natural rubber to form a composite material.     

Three Dimensional Monitoring of Stack Plume Dynamics by a Scanning Mie Lidar System as a Plume Watchdog Station

A scanning lidar system was developed to watch the nighttime diffusion process of plume from a smokestack of a large incinerator located around 3 km from the system. Observed data sets were visualized as three dimensional images in which could be seen the diffusion pattern from any direction, and this made it easy to investigate the exhaust dynamics. Observation results showed that the original plume extended at least 1.6 km, where there was a residential area, from the smokestack increasing in diameter to about 500 m. High density aerosols originating from the smokestack were measured in that area even at midnight. The lidar system performance as a plume watchdog station was discussed from the standpoint of publichealth-related plume monitoring.     

The Stability of Self-inclusion Complexes of Cyclodextrin Derivatives Bearing a p-Dimethylaminobenze Moiety

An appending moiety of modified cyclodextrins acts as an intramolecular guest and forms a self-inclusion complex in aqueous solution. In this study, the stability of self-inclusion complexes of modified cyclodextrins which have a p-dimethylaminobenzene moiety was analyzed by fluorescent decay analyses, and the factor that determines the stability of the self-inclusion complex was determined by a computational approach. The self-inclusion form is stabilized mainly due to van der Waals interaction between the appending moiety and the cyclodextrin ring.     

An Asymptotic Expansion Scheme for Optimal Investment Problems

We shall propose a new computational scheme for the evaluation of the optimal portfolio for investment. Our method is based on an extension of the asymptotic expansion approach which has been recently developed for pricing problems of the contingent claims’ analysis by Kunitomo and Takahashi (1992, 1995, 2001, 2003), Yoshida (1992), Takahashi (1995, 1999), Takahashi and Yoshida (2001). In particular, we will explicitly derive a formula of the optimal portfolio associated with maximizing utility from terminal wealth in a financial market with Markovian coefficients, and give a numerical example for a power utility function. This revised version was published online in June 2006 with corrections to the Cover Date.     

Step-wise decomposition process of azobenzene self-assembled monolayers

The step-wise decomposition of 4-(12-(dodecyldithio)dodecyloxy)azobenzene (AzoC24) in self-assembled monolayer (SAMs) on Au(1 1 1) was observed by thermal desorption spectroscopy (TDS) and X-ray photoelectron spectroscopy (XPS) under the ultra-high vacuum (UHV) condition. This decomposition process only occurred after the formation of the SAM.The TD spectra clearly showed two steps of thermal decomposition of the azobenzene moiety. At approximately 450 K, fragments of m/e = 77 and 105 were clearly observed. These fragments were decomposed species obtained by the breakage of the C-N bonds of the azobenzene moiety. At about 490 K, other fragment of m/e = 93 assigned to the phenoxy ion was detected. In order to examine the decomposition process, we measured the S 2p and N 1s XPS of the SAM at various temperatures. The results suggest that diazonium moiety is the first to be decomposed and the remaining structure is desorbed together with breakage of C-O bond between the phenoxy moiety and alkyl chain with increasing temperature.     

Control of diameter,morphology, and structure of PVDF nanofiber fabricated by electrospray deposition

Poly(vinylidene fluoride) (PVDF) nanofibers were prepared by electrospray deposition (ESD). To control the diameter, morphology, and structure of PVDF nanofibers, some parameters were investigated, such as polymer concentration, nozzle‐to‐ground collector distance, feeding rate of the polymer solution, and applied voltage. The fabricated fiber was 80–700 nm in diameter. The increase in the polymer concentration caused an increase in the polymer viscosity and fiber diameter. At low polymer concentration (5 wt %), polymer nanoparticles were formed. An increase in applied voltage will increase the fiber diameter. Variation in the nozzle‐to‐ground collector distance did not result in significant changes in the fiber diameter. Increase in the feeding rate of the polymer solution decreased the fiber diameter. Differential scanning calorimetry (DSC) and wide angle X‐ray diffraction (WAXD) measurements showed that the melting point and total crystallinity were decreased. Fourier transform infrared spectroscopy (FTIR) measurement revealed that ESD process induced the formation of the oriented β‐phase PVDF structures. It was also demonstrated that the addition of hydrofluorocarbon solvent to polymer solution remarkably enhanced the formation of β‐phase crystalline structure of PVDF nanofiber. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 779–786, 2006     

Determination of peroxidase encapsulated in liposomes using homogentisic acid y-lactone chemiluminescence.

Homogentisic acid gamma-lactone (HAL) chemiluminescence (CL) was applied to the determination of horseradish peroxidase (HRP) encapsulated in liposomes. HRP was detected after the lysis of HRP-trapped liposomes with Triton X-100. CL response rate, detection limit and linear range of calibration curve for HRP in HAL CL were compared with those in piodophenol (p-IP)-enhanced luminol CL. Maximal light emission in HAL CL appeared more rapidly compared to that in p-IP enhanced luminol CL, thus resulting in remarkable reduction of CL measurement time. The detection limit for HRP in HAL CL was the same as that in p-IP-enhanced luminol CL. The linear range of calibration curve for HRP in HAL CL was improved by a factor of 50 compared with that in p-IP-enhanced luminol CL. From these results, it was found that HAL CL were superior to p-IP-enhanced luminol CL for the determination of HRP encapsulated in liposomes.     

Oxygen‐deficient strontium cobaltate,SrCoO2.64

Single crystals of strontium cobaltate, SrCoO_3−x, have been grown by the floating‐zone method in an oxy­gen flow. The compound crystallizes with the cubic perovskite structure, with Pmm symmetry, as determined by X‐ray diffraction. Refinement of the O‐atom site occupancy yields the chemical composition SrCoO_2.64 [x = 0.36 (3)]. The anisotropic displacement ellipsoids of the O atoms suggest that their positional disorder occurs in a direction perpendicular to that of the Co—O bonds.     

Phase Modulation Characteristics Analysis of Optically-Addressed Parallel-Aligned Nematic Liquid Crystal Phase-Only Spatial Light Modulator Combined with a Liquid Crystal Display

An optically addressed parallel-aligned nematic-liquid-crystal spatial light modulator (PAL-SLM) has been studied as a dynamic phase-only light modulation device. The phase modulation characteristics of the PAL-SLM using a liquid crystal display (LCD) as an addressing mask were investigated by analyzing diffraction efficiencies resulting from binary gratings projected from the LCD. A more than 2π phase-only modulation depth was achieved. The highest first-order diffraction efficiency of approximately 38% was also obtained; this is close to the theoretical limit. The experimental results of diffraction efficiencies depending on the phase modulation depth are in good agreement with the simulation for the system operation.     

Highly Chemo‐, Regio‐, and Enantioselective Rhodium‐Catalyzed Cross‐Cyclotrimerization of Two Different Alkynes with Alkenes

It has been established that a cationic rhodium(I)/(R)‐tol‐binap complex catalyzes the cross‐cyclotrimerization of silylacetylenes, di‐tert‐butyl acetylenedicarboxylates, and acrylamides with excellent chemo‐, regio‐, and enantioselectivities. Unsymmetrical alkynoates can also be employed in place of di‐tert‐butyl acetylenedicarboxylate for this process, but with reduced chemoselectivity.